Butterworth filter . A frequency filter characterized by a very flat passband, often used as an alias filter. Sometimes called a maximally flat filter or trapezoidal filter (Sheriff and Geldart, 1995).

macroclimate (mac-ro-cli'-mate). The general climate of an extensive region or a country. See also: mesoclimate; microclimate.

fumarole mound . A small mound from which fumarole or solfatara gases escape.

alumino-katophorite . A hypothetical member of the amphibole mineral family; probably an unnecessary name for katophorite : Na2Ca(Fe2+4Al)(Si7Al)O22(OH)2.

clarotelain (clar-o-te'-lain). A transitional lithotype of coal characterized by the presence of telinite, with lesser amounts of other macerals. Cf: teloclarain. Syn: clarotelite.

greenstone [meta] . A field term applied to any compact dark-green altered or metamorphosed mafic igneous rock (e.g., spilite, basalt, gabbro, diabase) that owes its color to the presence of chlorite, actinolite, or epidote.

anticyclone (an-ti-cy'-clone). An atmospheric high-pressure system with closed isobars, the pressure gradient being directed away from the center so that the near surface wind spirals outward in a clockwise direction in the Northern Hemisphere, counterclockwise in the Southern. It was named by Francis Galton in 1861. See also: cyclone.